Alpine on OpenBSD's vmd(8)

These are my notes on setting up Alpine Linux as a guest under OpenBSD's native vmd(8) hypervisor. This is useful way to gain access to Linux on an OpenBSD host. One can easily run Docker, Portainer, and other typically Linux-oriented software from the comfort of OpenBSD. :)

Be sure to review the man pages

$ man vmm # virtual machine monitor
$ man vmd # virtual machine daemon
$ man vm.conf

Check if your system can run vmd

$ dmesg | grep vmm >/dev/null && echo ye || echo ni

Enable vmd

$ doas rcctl enable vmd
$ doas rcctl start vmd

Create the VM directory

Create your directory somewhere nice, examples:

$ mkdir -p /home/cosmic/vmm
$ mkdir -p /home/vmm

Tip: If you need more space on an existing system, you may be able to collapse /src and /obj into a single partition and remount it as /home/vmm, if needed.

Create the VM disk

$ vmctl create -s 2G alpine-virt-aarch64.qcow2
vmctl: qcow2 imagefile created

Getting the Alpine ISO

First, I went to Alpine's download page to grab the URL to the latest virt X86_64 Alpine ISO:

> Similar to standard. Slimmed down kernel. Optimized for virtual systems.

In this case it yielded this link:

https://dl-cdn.alpinelinux.org/alpine/v3.18/releases/x86_64/alpine-virt-3.18.2-x86_64.iso

If you are running on arm64 (e.g. Raspberry Pi) be sure to grab the corresponding aarch64 Alpine ISO:

https://dl-cdn.alpinelinux.org/alpine/v3.20/releases/aarch64/alpine-virt-3.20.3-aarch64.iso

ftp will grab it easily and quickly.

$ cd /home/cosmic/vmm
$ ftp $ALPINE_ISO_URL

Other notes

The key things I wanted to note:

If you're SSHed into the box and need to leave the virtual console, use ~~. and type the tildes somewhat rapidly. Plain ~. will drop your ssh session, but you're using tmux anyway, right?
Next, the host dhcpleased was stealing the DHCP packets destined for the VM. I needed to rcctl stop dhcpleased before I could get a lease in the VM. Source

VM configuration

This will need to be edited as root. An example file can be read here:

$ less /etc/examples/vm.conf

Here's my /etc/vm.conf with disk commented out since we need to boot the ISO first:

vm "alpine" {
    boot device cdrom # disk
    cdrom "/home/cosmic/vmm/alpine-virt-3.20.3-aarch64.iso"
    disable
    disk "/home/cosmic/vmm/alpine-virt-aarch64.qcow2"
    interface tap0 {
        up
    }
    owner cosmic:wheel
    memory 256M
}

Check your config

$ doas vmd -dnv
configuration OK

Alpine setup

I chose to use openntpd as my NTP server, I like OpenBSD software (as you might be able to tell). Supposedly chrony is more accurate, e.g. subsecond precision, but that doesn't matter for me. Kinda silly but it also reminds me of "crony":

While a crony is basically just a good pal or sidekick, the word sometimes has a negative connotation — that you and your crony are up to no good together.

You can test dhcp before running alpine-setup with udhcpc eth0. Make sure eth0 is up first.

Post setup

With Alpine running successfully, we can install Docker now:

# visudo
Add this line: user ALL=(ALL) ALL

apk add docker docker-cli-compose